Support for Scala3 opaque types?

[kadriaen]

Not sure if I'm missing something here but....
The following code snippet gives me an 'Infinite loop in function body' compile error.

import upickle.default.ReadWriter

opaque type Isbn = String
object Isbn {
  def apply(id: String): Isbn = id
  extension (Isbn: Isbn) {
    def asString: String = Isbn
  }
  given ReadWriter[Isbn] = {
    upickle.default
      .readwriter[String]
      .bimap[Isbn](
        isbn => isbn.asString,
        str => Isbn(str)
      )
  }
}

Error:

[error] 11 |  given ReadWriter[Isbn] = {
[error]    |                           ^
[error]    |Infinite loop in function body
[error]    |{
[error]    |  upickle.default.readwriter[String](
[error]    |    be.bitmetric.microtickets.model.common.isbn.Isbn.given_ReadWriter_Isbn).
[error]    |    bimap[be.bitmetric.microtickets.model.common.isbn.Isbn$package.Isbn](
[error]    |    {
[error]    |      def $anonfun(
[error]    |        isbn²: be.bitmetric.microtickets.model.common.isbn.Isbn$package.Isbn):
[error]    |        String =
[error]    |        be.bitmetric.microtickets.model.common.isbn.Isbn.asString(isbn²)
[error]    |      closure($anonfun)
[error]    |    },
[error]    |    {
[error]    |      def $anonfun²(str: String):
[error]    |        be.bitmetric.microtickets.model.common.isbn.Isbn$package.Isbn =
[error]    |        be.bitmetric.microtickets.model.common.isbn.Isbn.apply(str)
[error]    |      closure($anonfun²)
[error]    |    }
[error]    |  )
[error]    |}
[error]    |
[error]    |where:    $anonfun  is a method in the initializer of given instance given_ReadWriter_Isbn
[error]    |          $anonfun² is a method in the initializer of given instance given_ReadWriter_Isbn
[error]    |          isbn      is a package in package be.bitmetric.microtickets.model.common
[error]    |          isbn²     is a parameter in an anonymous function in the initializer of
[error]    |  given instance given_ReadWriter_Isbn
[error] 12 |    upickle.default
[error] 13 |      .readwriter[String]
[error] 14 |      .bimap[Isbn](
[error] 15 |        isbn => isbn.asString,
[error] 16 |        str => Isbn(str)
[error] 17 |      )
[error] 18 |  }

I can obviously work around this by turning all opaque types into final case classes, but I'm wondering if there's a workaround to get these trivial opaque types to work with uPickle?